The iron law of imprisonment is that “they all come back”. In 2002, more than 630,000 individuals left U.S. federal and state prisons. Thirty years ago, only 150,000 did. In this study, Travis decribes the new realities of imprisonment, and explores the impact of returning prisoners on seven policy domains: public safety, families and children, work, housing, public health, civic identity, and community capacity. Travis proposes a new architecture for the criminal justice system, organized around five principles of reentry, to encourage change and spur innovation.